Patterning of flow and mixing in rotating radial microchannels

Abstract

We demonstrate how the speed of mixing under laminar conditions can be appreciably enhanced in concurrent centrifugal flows through straight, low-aspect-ratio microchannels pointing in radial direction in the plane of rotation. The convective mixing is driven by the inhomogeneous distribution of the velocity-dependent Coriolis pseudo force and the interaction of the soinduced transverse currents with the side walls. By investigating the key impact parameters, which are the geometry of the channels and the speed of rotation, it is shown that the contact surface between two laminar flows can be folded to shorten mixing times by up to two orders of magnitude!

Microfluidic platforms for lab-on-a-chip applications

“…Considering mixing of continuous liquid flows within a radially directed rotating channel, the perpendicularly directed Coriolis force f C automatically generates a transverse liquid flow. 55,61,62 A continuous centrifugal micromixer, utilizing the Coriolis stirring effect, showed an increasing mixing quality towards very high volume throughputs of up to 1 mL s 21 per channel. 55 Besides the mixing of continuous liquid flows, the homogenization of discrete and small liquid volumes located in chambers is also of importance, especially when analyzing small sample volumes (batch mode mixing).…”

Biosensing enhancement of dengue virus using microballoon mixers on centrifugal microfluidic platforms

“…Advection mechanism in both active mixers is induced by the relative motion of magnets that were embedded inside these mixing chambers, in respect to the external magnetic forces (Ducrée et al, 2007;Grumann et al, 2005;Haeberle et al, 2005). Passive mixing principles that have been explored on the centrifugal microfluidics include multilamination technique, reciprocating flow, Coriolis pseudo-force and Stopped-flow (passive batch-mode) mixing (Ducree et al, 2006;Ducrée et al, 2006Ducrée et al, , 2007Grumann et al, 2005;Haeberle et al, 2005;Kinahan et al, 2014;Noroozi et al, 2009;Ren and Leung, 2013a;Steigert et al, 2005). Stopped-flow mode mixing is based on inertia induced by the reversal of the spinning direction, hence it is commonly used in complex bioassays where the efficient use of the limited space on the disk is crucial .…”

Light-Actuated Push/Pull Manipulation of Liquid Droplets

“…In the field of micro-optics, control of liquids has become a viable sub-discipline for adaptive optics, allowing the fabrication of tunable lenses [1] or phase-manipulating micromirrors [2]. Several competing techniques have been demonstrated for liquid manipulation, such as the use of rotational forces [3] or electroosmotic flow [4]. The use of electrowetting to control the wetting behavior of a droplet is very promising, due to the simple structures and low power consumption required, as well as the achievable switching times in the millisecond range.…”